Accuracy & Estimation (DP IB Applications & Interpretation (AI)): Revision Note

Accuracy & Estimation

What are exact values?

• An exact value is a representation of the full and precise value of a number

  • For example

    • fractions,   

    • roots, ,  

    • logarithms, , 

    • mathematical constants, , 

• When using decimals, three dots means the decimals keep going forever

  • e.g.

What is estimation?

• Estimation means rounding numbers to easier values before doing a calculation with them

• Estimation is used for rough answers or checking a method

  • e.g. if your method for finding the mean age of students gives a rough answer of 200, the method needs revisiting

How do I choose the correct answer?

• If a mathematical argument gives more than one answer, use logic to choose the correct one

  • e.g. if solving an equation gives a side length as either or , choose the positive one

    • Lengths cannot be negative